Author Topic: Sun Shade concepts for Venus  (Read 41827 times)

Offline RanulfC

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Re: Sun Shade concepts for Venus
« Reply #180 on: 03/14/2012 01:06 PM »
Andrew_W:
I understand the idea to be artificial "upwellings" of surface air. Really tough to do considering the wind-shear difference between the surface and (say) 50km, but the idea would be to pump the hot surface air to high altitude before it could appreciably cool off. Once there it gives off it's heat rapidly and then begins to sink back towards the surface.

I got that right folks?

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Offline Andrew_W

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Re: Sun Shade concepts for Venus
« Reply #181 on: 03/14/2012 02:39 PM »
I confess that in 1901 I said to my brother Orville that man would not fly for fifty years.
Wilbur Wright

Offline RocketmanUS

Re: Sun Shade concepts for Venus
« Reply #182 on: 03/15/2012 12:07 AM »
Radical Terraforming Methods
http://forum.nasaspaceflight.com/index.php?topic=25012.0

Splinter threads for terraforming Venus and removing some of it's CO2.
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Offline RocketmanUS

Re: Sun Shade concepts for Venus
« Reply #183 on: 03/16/2012 12:12 AM »
Once the Sun shade blocks the incoming heat and the atmosphere cools,
How deep would the body of liquid CO2 be or if it's dry ice be? ( for this just assume Venus surface is flat no valleys or hills )
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Offline Andrew_W

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Re: Sun Shade concepts for Venus
« Reply #184 on: 03/16/2012 12:30 AM »
Dry ice is about 1.5 times as dense as water, at 90 atmospheres pressure  on a planet with 0.9 g surface gravity you've got about 1000 tonnes of atmosphere over each square meter. So Venus has enough CO2 to give a layer of dry ice 660 meters thick over the whole planet, pile it up in one place to have maybe 6600 meters thick over 10% of the planet.
I confess that in 1901 I said to my brother Orville that man would not fly for fifty years.
Wilbur Wright

Offline RocketmanUS

Re: Sun Shade concepts for Venus
« Reply #185 on: 03/16/2012 12:43 AM »
Dry ice is about 1.5 times as dense as water, at 90 atmospheres pressure  on a planet with 0.9 g surface gravity you've got about 1000 tonnes of atmosphere over each square meter. So Venus has enough CO2 to give a layer of dry ice 660 meters thick over the whole planet, pile it up in one place to have maybe 6600 meters thick over 10% of the planet.
That means the high areas of the surface could be exposed for landing and exploration.

We would still have a nitrogen atmosphere. 3.5% is nitrogen, now it would be the main compound for the atmosphere.
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Offline yawan

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Re: Sun Shade concepts for Venus
« Reply #186 on: 08/02/2017 01:47 AM »
I'm making very rough calculations so please correct me if I'm wrong, but here is an idea.
Coat graphane with a thin layer of reflective metal.  Release it in a spiral in around L1.  Make sure the gravity and solar pressure are around equal.  Release it close to the SUN.  If you can get the calculations done right you can block out the sun for a while.  If you can keep it up long enough you can cool the planet past 3 and 4 um absorption frequencies to the equilibrium around 40 degrees Celsius and 8 atm of pressure 3 atm nitogen and 5 atm co2.  The rest of CO2 would form an ocean, and sulfuric acid would reach with the rock and form water.  You could still live at around 10-15 km in floating cities, but robotic mining would be a lot easier, and you would have water.

Offline high road

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Re: Sun Shade concepts for Venus
« Reply #187 on: 08/02/2017 07:25 AM »
I'm making very rough calculations so please correct me if I'm wrong, but here is an idea.
Coat graphane with a thin layer of reflective metal.  Release it in a spiral in around L1.  Make sure the gravity and solar pressure are around equal.  Release it close to the SUN.  If you can get the calculations done right you can block out the sun for a while.  If you can keep it up long enough you can cool the planet past 3 and 4 um absorption frequencies to the equilibrium around 40 degrees Celsius and 8 atm of pressure 3 atm nitogen and 5 atm co2.  The rest of CO2 would form an ocean, and sulfuric acid would reach with the rock and form water.  You could still live at around 10-15 km in floating cities, but robotic mining would be a lot easier, and you would have water.

I hope you've done the calculation for negative 40 degrees C, for the CO2 to become liquid. Any remaining water will float as ice on top of the CO2 ocean. Probably none, as it will have been transformed into bicarbonates during the cooling of the planet. Sulfuric acid will no longer be a problem, although the SO2 will take longer to react with rock surfaces.

Keeping the habitat comfortably warm, after stripping away most of the energy sources, is going to be a challenge.

Offline yawan

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Re: Sun Shade concepts for Venus
« Reply #188 on: 08/02/2017 03:36 PM »
No my pressure was off for calculating the pressure at which CO2 becomes liquid.
Cooling Venus temporarily past its 4um equilibrium would cool it to around 10 um average frequency.
https://scholarsandrogues.files.wordpress.com/2011/05/venus-co2-spectrum-lg.jpg
That would equate to around 40 degrees Celsius.  It would keep the pressure, but all the electronics would work on the surface, which would make mining plausible.
Some reactions would form bicarbonates.
Those bicarbonates would create sodium and magnesium bicarbonates which react with sulfuric acid to form water... so we'd end up with oceans soon enough.
And there are plenty of reactions that would create water straight away.
I'm not saying all the sulfuric acid would become water but most of it would.

Offline stefan r

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Re: Sun Shade concepts for Venus
« Reply #189 on: 08/07/2017 02:00 PM »
No my pressure was off for calculating the pressure at which CO2 becomes liquid.
Cooling Venus temporarily past its 4um equilibrium would cool it to around 10 um average frequency.
https://scholarsandrogues.files.wordpress.com/2011/05/venus-co2-spectrum-lg.jpg
That would equate to around 40 degrees Celsius.  It would keep the pressure, but all the electronics would work on the surface, which would make mining plausible.
Some reactions would form bicarbonates.
Those bicarbonates would create sodium and magnesium bicarbonates which react with sulfuric acid to form water... so we'd end up with oceans soon enough.
And there are plenty of reactions that would create water straight away.
I'm not saying all the sulfuric acid would become water but most of it would.

Mercury has a lower gravity and a lot of metal.  Mercury mines could out compete Venus.  The inner solar system will have a strong demand for carbon and hydrogen.  If your motive for colonizing Venus is strip mining then the atmosphere is the commodity not the obstacle.

Oxygen balloons float in a CO2 atmosphere. 

Tethers can be used to change the velocity of spacecraft.  If Venus manufactures graphene or fullerene tethers then cargo transports could use Venus's gravity for an orbital assist and take a tether with them too. 

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